Regular motorcycle and automobile tires do not have an inner tube. When a pointed object pierced the tire of a motor vehicle, air does not immediately leak out. However, if the motor vehicle keeps running for a certain length of time after piercing of a pointed object through one tire thereof, the tire may explode, causing a catastrophe. In order to eliminate this problem, "high-speed" tires are developed. A "high-speed" tire is made of elastic material of high density. When pierced by a pointed object, the tire does not leak immediately, and the car driver has sufficient time to repair the tire. However, because this structure of tire does not leak immediately when pierced by a pointed object, the car driver may not find the problem before an accident occurs. U.S. patent application Ser. No. 09/193,232, entitled "Vehicle inner tube with protective breaker means", teaches a measure to eliminate the aforesaid problem. The vehicle inner tube according to U.S. patent application Ser. No. 09/193,232 is functional, however its structure is complicated, and its manufacturing cost is high.